1. Field of the Invention
The present invention relates to a lockable structure for a big-handle lock.
2. Description of the Related Art
Taiwan Utility Model Publication No. 122820 issued on Nov. 11, 1989 and entitled "TRANSMISSION MECHANISM FOR A BIG-HANDLE LOCK" discloses a so-called big-handle lock comprising a seat assembly and a transmission assembly. The seat assembly includes a receiving member, a press member, and a pivotal pin. The transmission assembly includes a cover plate, a push-button rod, a connecting plate, a transmission plate, a fixing button, an actuating spring, a transmission rod, and a bottom plate. The big-handle lock is mounted to a door to allow easy opening of the door, which is particularly suitable for a heavy door. When the push-button rod is pushed, the transmission rod 26 is rotated for retracting a latch bolt to allow opening of the door. Nevertheless, the big-handle lock cannot provide locking function such that an additional lockable structure is required. As a result, installation and use of the big-handle lock and the additional lockable structure are inconvenient.